I suppose I should have actually mentioned this in the first place.
The entire point of having there be an extreme increase in xp needed to level is to create a maximum level without an actual "final level". Essentially, in order to balance a game where each person can assign their own attributes and skills you have to be able to know what the average number of those attributes and skills is going to be, and what the maximum number of those attributes and skills could be. You have to set limits on the types of builds people can have, without actually setting any un-natural caps, in order to figure out basically everything else in balancing. What damage weapons should have, what max level your server/net-code can actually handle, etc.
It's actually probably one of the most amazing and yet unmentioned triumphs of crpg in the first place. The vast majority of multi-player games have either strict base attributes, or extremely linear upgrade options specifically because it is so difficult to balance otherwise.
As to your point about increasing the level cap. I seriously doubt having many people at level 39 or 40 or 41 would be healthy for the mod. Instead of thinking 0f the increase in xp as unfair, just think of level 37 as the max level, and level 38 as the max+1 level for the super dedicated.